The present invention relates in general to cellular communications or telephone systems and, more particularly, to methods for controlling the operations of such systems based on mobility and teletraffic statistics of mobile units operating within the system. In the present invention, mobile units collect their own mobility and teletraffic statistics and transmit aggregated statistics to base stations for control of the cellular system.
In state-of-the-art cellular communications or telephone systems, mobile units operating within a system monitor radio channels. The mobiles detect radio channels and accumulate data related to the radio channels such as signal strength, signal-to-noise ratio and the like. This information is provided to base stations distributed throughout the cellular system such that the mobile units assist in selection of appropriate channels and cells within the cellular system to help ensure the most satisfactory reception for each of the mobiles.
As the popularity of wireless communications increases, the number of mobile units within any given cellular system will also increase such that more mobile units will have to be handled by the cellular systems. One approach to increased capacity for handling higher mobile densities is the use of hierarchical architectures. In such architectures, a grid of microcells is overlaid with a grid of larger macrocells with overlapping coverage areas. Each microcell includes a base station which controls and coordinates mobile units within the microcell and each macrocell includes a base station which supervises mobile units under its control and coordinates a plurality of microcell base stations which are within the macrocell. When a mobile unit leaves one microcell and enters another microcell, it is handed-off from the base station of the first microcell to the base station of the second microcell. In areas where coverage is possible from either a microcell or a macrocell, the cellular system must determine whether to assign each call at origination and handoff, to a microcell or to a macrocell.
There is a need for an improved arrangement for controlling the operation of cellular systems which makes efficient use of network resources. Preferably, the improved arrangement would assist in determining whether a call, originating or handoff, should be assigned to a microcell or a macrocell in hierarchical architectures and not add substantially to the processing burden which is placed on microcell and macrocell base stations, and the network associated with a cellular system.